MRI - ultrasound fusion guided biopsy of the prostate: lesion volume as a predictor of cancer in patients with repeat biopsies.

INTRODUCTION: The objective was to analyze the diagnostic value of multiparametric magnetic resonance imaging (MRI) prostate lesion volume (PLV) and its correlation with the subsequent MRI-ultrasound (MRI-US) fusion biopsy results. MATERIALS AND METHODS: Between March 2014 and July 2016, 150 men underwent MRI-US fusion biopsies at our institution. All suspicious prostate lesions were graded according to the Prostate Imaging Reporting and Data System (PIRADS) and their volumes were measured. These lesions were subsequently biopsied. All data were prospectively collected and retrospectively analyzed. The PLV of all suspicious lesions was correlated with the presence of cancer on the final MRI-US fusion biopsy. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated. RESULTS: There were 206 suspicious lesions identified in 150 men. The overall cancer detection rate was 102/206 (49.5%). The mean PLV for benign lesions was 0.63 ± 0.94 cm3 versus 1.44 ± 1.76 cm3 for cancerous lesions (P < 0.01). There was a statistically significant difference between the PLV of PIRADS 5 lesions when compared to PIRADS 4, 3, and 2 lesions (P < 0.0001, < 0.0001, and 0.006, respectively). The area under the curve for volume in predicting prostate cancer (PCa) was 0.66. The optimal volume for predicting PCa was 0.26 cm3 with a sensitivity, specificity, PPV, and NPV of 80.7%, 42.7%, 41.2%, and 74.6%, respectively. CONCLUSION: PLV may serve as a useful measure to triage patients prior to MRI-US fusion biopsy and help better understand the limits of this technology for individual patients.

Natural Orifice Transluminal Endoscopic Partial Prostatectomy: A Real-time Image-guided Focal Extirpative Feasibility Study.

OBJECTIVE: To assess the feasibility of focal endoscopic excision of prostate cancer (PCa) under guidance of real-time magnetic resonance imaging (MRI) or magnetic ultrasound fusion (MUF). MATERIALS AND METHODS: Using a cadaveric model, multifocal PCa was simulated using 2 MRI-compatible fiducial markers. These were inserted transrectally and used to generate regions of interests (ROIs) on a 1.5-T surface-coil MRI. The first marker was placed in the right mid-peripheral zone (ROI 1), and the second marker was placed in the left seminal vesicle as a referent lesion for subsequent imaging. MRI of the specimen was then obtained. The radiologist created ROIs using fusion biopsy system at each marker. Two additional incidental ROIs were identified in the left transitional zone (ROI 2-suspicious for benign prostatic hyperplasia nodule) and in the right anterior peripheral zone (ROI 3-suspicious for PCa). Holmium laser enucleation of the transitional zone of the prostate was performed to gain access to the peripheral zone lesions. MUF was used during endoscopic laser excision to convey targeting accuracy. The cadaver was then reimaged to determine the adequacy of resection and examined for histopathologic correlation. RESULTS: Real-time MUF imaging identified the target lesions consistently at the locations designated as ROIs. Complete endoscopic resection of ROIs was possible. Repeated MUF imaging and the postprocedure MRI confirmed the completeness of resection. Pathologic examination demonstrated complete excision, intact neurovascular bundles, and posterior prostatic capsule. CONCLUSION: This approach may represent a new minimally invasive frontier for focal surgical resection of PCa, making histopathologic margin status determination possible.

Infectious complications associated with the use of temporary prostatic urethral stents in patients with benign prostatic hyperplasia.

INTRODUCTION: To examine the infectious outcomes after the insertion of the temporary prostatic urethral stent (TPUS) in benign prostatic hyperplasia (BPH) patients. MATERIAL AND METHODS: Between November 2007 and September 2012, ninety TPUS were used in 33 patients with BPH at our institution. All patients had negative urine cultures prior to the first stent insertion. TPUS were sent for cultures at time of removal or exchange. Stents were removed at the time of definite surgical intervention, at 4-6 weeks, or when patients elected another course of treatment. Colonization was defined as asymptomatic positive stent culture. Infection was defined as symptomatic positive stent culture requiring treatment. Infection and colonization rates are reported. Logistic regression was used to examine the predictors of infection at any point. Predictors examined were age, body mass index, history of prostate cancer, diabetes mellitus, hyperlipidemia, coronary artery disease, neurologic disorder, erectile dysfunction and the sequence of stent placement. RESULTS: The majority of the subjects, 72% (24/33) had 1-2 stents, 9.0% (3/33) had 3-4 stents, 6.0% (2/33) had 5-6 stents, and 12% (4/33) of patients had more than 6 stents. From the 69 available culture results, the symptomatic infection rate was 16% (11/69) (95% CI: 8.2%-26.7%). The colonization rate was 58% (40/69) (95% CI: 45.5%-69.7%). None of the predictors examined were identified as a predictor of infection. There was no colonization detected when stents were removed in the first 20 days. CONCLUSION: Infection rates with TPUS in BPH patients are acceptable and early removal may prevent colonization.